The present invention relates to a vehicle with a driver's cab comprising a driver seat unit with a vertically suspended floor structure including means for steering control, means for speed control and a driver's seat.
The driver seating arrangement for heavy trucks and heavy construction vehicles usually comprises a seat with suspension for driver comfort. One disadvantage with seat suspension is that the seat moves up and down when driving over road surface deviations, in relation to the steering wheel, the pedals and other vehicle controls. Thus, the vertical movements can make it more difficult to control a heavy vehicle in a tight situation.
Also, the vertical movements of the driver may reduce the quality of sensor data used as input to systems for driver awareness detection. For example, these systems often use input data from different vehicle control sensors to monitor driver awareness.
For example U.S. Pat. No. 3,774,711 discloses a drivers cab with a seat mounted on a platform that includes a steering wheel and foot pedals. The platform is mounted to the cab floor via a vertical suspension system.
A heavy truck used for long distance hauling needs a driver's cab which is flexible to provide an ergonomic workplace when driving on the road, and also to provide a functional living space when resting in between driving times. As the total length of the vehicle is limited in many countries, cab length is limited to maximize cargo capacity. When a suspended driver platform as described above is applied to this type of vehicle, the suspended platform will normally consume a large part of the available floor space. The suspended platform does not provide a stable surface for moving around inside the cab when parked, and could be a potential safety risk for the driver. Also, when the driver leaves the suspended platform for exiting the cab, the driver has to climb down a number of vertical steps from a considerable height, often about 1.5 meters above ground. Initially, the driver must transfer his weight from the suspended platform to the cab frame or to the uppermost step. As a consequence of the weight transfer, the platform moves upwards until it reaches a top position. This problem may also exist at construction vehicles.
Usually, the driver's seat is located close to a side door of the cab. Thus, the driver has very little room for safe movement near to a considerable vertical drop.
It is desirable to provide a vehicle with a suspended driver's platform in which the above described problems are minimized.
According to an aspect of the invention, the driver's cab is provided with a locking mechanism for preventing the floor structure from moving vertically in relation to the cab when the vehicle is immobile.
The locking mechanism is preferably operated by means of a parking brake system to prevent the suspended floor structure from moving vertically when the parking brake system is activated.
Preferably, the floor structure is arranged in a cab with a primary floor and a secondary floor positioned a certain distance below the primary floor.
Advantageously, the floor structure is adapted to be restrained in a first mode of position level with the primary floor of the vehicle.
According to an advantageous embodiment of the invention, the floor structure is able to release and reposition itself from said first mode of position to a second mode of position below said first mode of position, to form a step for climbing into and out of the driver's cab.
Preferably, the repositioning of the floor structure between said two modes of position is actuated by means of the opening and closing of the driver's door, so that the floor structure is lowered to the second mode of position when the driver's door is opened and raised to the first mode of position when the driver's door is closed. Advantageously, actuation of repositioning of the floor structure via opening and closing of the driver's door can be switched on and off.
According to a preferable embodiment of the invention, the floor structure is suspended by means of a pneumatically controlled spring system.
According to still another embodiment of the invention, the pneumatically controlled spring system is adapted to control seat ride height relative to driver weight. Also, the pneumatically controlled spring system can be adapted to control seat ride height in relation to driver length.
Preferably, vertical motion of the floor structure is controlled by means of a hydraulic piston.
Further embodiments of the invention are illustrated and explained in the figures.